WASHINGTON -- It is said, more frequently than precisely, that the reasons the Supreme Court gives for doing whatever it does are as important as what it does. Actually, the court's reasons are what it does. Hence, the interest in the case the Supreme Court considered last week.

It probably will result in a routine ruling that extends a 2008 decision and renders dubious many state and local gun control laws. What could -- but, judging from the justices' remarks during oral argument, probably will not -- make the ruling momentous would be the court deciding that the two ordinances at issue violate the 14th Amendment's "privileges or immunities" clause. Liberals and conservatives submitted briefs arguing, correctly, that this clause was intended to be a scythe for slicing through thickets of state and local laws abridging fundamental liberties.

The Second Amendment says: "A well-regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed." Until 2008, the court had never clarified whether the prefatory clause makes this right conditional: Does the amendment protect an individual's right to own firearms, or does it protected that right only in connection with a state's right to organize a militia?

In 2008, the court struck down a District of Columbia law that effectively banned possession of handguns even in an owner's home -- it banned all guns not kept at businesses, or disassembled or disabled by trigger locks. The court held, 5-4, that the Second Amendment protects individuals' rights.

But the court answered only the question then posed, which concerned the federal enclave of D.C. Left unanswered was whether the amendment protects that right against severe restrictions by state and local laws.

The oral argument concerned ordinances in Chicago and suburban Oak Park that are indistinguishable from the D.C. law. The court probably will overturn those ordinances by holding that another part of the 14th Amendment -- the guarantee that no state shall deny liberty "without due process of law" -- "incorporates" the Second Amendment. The justices evinced scant interest Tuesday in resurrecting the "privileges or immunities" clause by revisiting an incoherent decision rendered in 1873.

To the drafters of the 14th Amendment, the phrase "privileges or immunities" was synonymous with "basic civil rights." But in 1873, the court held that only some of the rights enumerated in the Bill of Rights restrict states by being "incorporated" into the 14th Amendment's "due process" clause.

Since 1897, the court has held, with no discernible principle, that some rights enumerated in the Bill of Rights are sufficiently fundamental to be "incorporated" but others are not. This doctrine bears the oxymoronic name "substantive due process." Substance is what process questions are not about.

If the court now "incorporates" the Second Amendment right via the "due process" guarantee, that will be progress because it will enlarge the sphere of protected liberty. And even Justice Antonin Scalia, who recognizes that "substantive due process" is intellectual applesauce, thinks it is too late to repudiate 137 years of the stuff. Still, three points argue for using the "privileges or immunities" scythe against the two gun ordinances.

First, protecting the individual's right to keep and bear arms for self-defense was frequently mentioned by those who drafted and ratified the 14th Amendment, the purpose of which was to protect former slaves and their advocates from being disarmed by state and local governments determined to assault their security and limit their autonomy.

Second, the central tenet of American political philosophy is that government is instituted not to bestow rights but to protect pre-existing rights, aka natural rights -- those essential to the flourishing of our natures. In its 2008 decision, the court affirmed that the Second Amendment did not grant a right to keep and bear arms, it "codified a

pre-existing right."

Third, "privileges or immunities" are all those rights that, at the time the 14th Amendment was ratified, were understood to be central to Americans' enjoyment of the blessings of liberty.

Liberals might hope and conservatives might fear that a revivified "privileges or immunities" clause wielded by liberal justices would breed many new "positive rights" -- to welfare, health care, etc. But conservatives know that "substantive due process" already has such a pernicious potential. And they believe that if -- a huge caveat -- it remained tethered to the intent of its 19th-century authors, the "privileges or immunities" clause would be useful protection against the statism of the states.